Conventionally, as a gas turbine system including a gas turbine unit, there has been known a cogeneration system that produces hot water, etc. by utilizing the waste heat caused when the gas turbine unit generates electricity. In recent years, there also has been proposed a gas turbine system that directly produces hot water and cold air by using a gas turbine unit without generating electricity. For example, Patent Literature 1 discloses a gas turbine system 100 as shown in FIG. 6.
The gas turbine system 100 includes a first compressor 101 and a first expansion turbine 102 coupled to each other by a shaft, a combustor 103, a regenerative heat exchanger 104, and a heat exchanger 123 for hot water, as elements constituting a gas turbine unit. The first compressor 101 compresses air taken from atmosphere. The air discharged from the first compressor 101 passes through the regenerative heat exchanger 104, and then flows into the combustor 103. A fuel is injected into the combustor 103 and combusted therein. A combustion gas generated in the combustor 103 heats the air to flow into the combustor 103 in the regenerative heat exchanger 104, and then flows into the first expansion turbine 102 to be expanded therein. The first expansion turbine 102 creates power from the expanding combustion gas as a rotation torque to drive the first compressor 101. The combustion gas discharged from the first expansion turbine 102 is utilized, in the heat exchanger 123 for hot water, as a heat source for producing hot water, and then exhausted into the atmosphere.
In the gas turbine system 100, the gas turbine unit has no power generator. Thus, in order to start the gas turbine unit, the gas turbine system 100 is provided with a reciprocating type compressor 105 for supplying compressed air to the combustor 103 at the time of starting.
Furthermore, the gas turbine system 100 has a configuration to extract, from the gas turbine unit, the air compressed in the first compressor 101 and lower the temperature of this extracted air (so-called bleed air) so as to produce cold air. Specifically, the gas turbine system 100 is provided with a first heat exchanger 121 for cooling the air extracted from the gas turbine unit with cold water, a second compressor 111 for compressing the air that has flowed out of the first heat exchanger 121, a second heat exchanger 122 for cooling the air discharged from the second compressor 111 with cold water, and a second expansion turbine 112 for expanding the air that has flowed out of the second heat exchanger 122. The second expansion turbine 112 is coupled to the second compressor 111 by a shaft, and creates power from the expanding air as a rotation torque to drive the second compressor 111. A moisture separator 113 for separating moisture from the air is provided between the second heat exchanger 122 and the second expansion turbines 112. The water heated by cooling the air in the first heat exchanger 121 and the second heat exchanger 122 is supplied to the heat exchanger 123 for hot water in the gas turbine unit.